In America an obese (a fatty)
person, in some cases is frowned upon. Majority of Americans dislike the human
fat, which is scorned and despised and ruthlessly vacuumed from bellies and
backsides by suction-assisted lipectomy (i.e., liposuction) may have a redeeming
feature after all. This much-accused tissue appears to be a rich source of stem
cells, prized by scientists for their seemingly magical power to turn into a
variety of tissue types. These tissues can be replacements for almost any part
of the human body without the problems of rejection. Rejection is a colossal
problem currently in human organ transplants.

What are Stem Cells?

Stem cells are living cells that
can develop into many different types of tissue, such as bone, muscle or brain.
There are three basic types: (1) "Totipotent" stem cells These cells are formed
when a fertilized egg first divides- can turn into any type of tissue and form a
"total" organism. After five days after fertilization, a hollow ball of about
100 cells called a blastocyst forms. The cells on the outside develop into the
placenta, while those on the inside turn into the embryo itself. (2) The 50 or
so inner cells are "pluripotent" - they can turn into almost all types of
tissue, but not a whole organism. As the embryo develops further, stem cells
become (3) "multipotent" - they can give rise only to specific kinds of cells.
Totipotent and pluripotent cells are also known as adult stem cells.

What kind is useful?

If they had their way most
physicians would go for pluripotent stem cells because these can give all the
types of tissues one needs, but cannot turn into a whole human being.

From where to get them?

At present the only place to get
them is from human embryos, which is the one reason why pro-life groups are so
opposed to stem cell research. Three research groups around the world have found
ways to grow potentially limitless supplies of pluripotent cells in the lab -
but these did come from embryos in the first place. If a patient were given
organs grown from somebody else's cells, the patient has to take
immunosuppressant drugs for the rest of his or her life.

Obtaining stem cells-primitive
cells with the potential to become virtually any type of tissue-from adipose
tissue or fat collected by liposuction - a cosmetic procedure - and converted
them into becoming muscle, bone or cartilage, depending on the conditions in
which they were grown, scientists, reported in the journal Tissue
Engineering (Volume 7, Number 2: 211-218, April 2001). This article
titled "Multilineage cellsfrom human adipose tissue: implications for
cell-based therapies, was authored by Zuk PA, Zhu M, Mizuno H, Huang J, Futrell
JW, Katz AJ, Benhaim P, Lorenz HP, Hedrick MH of the Laboratory for Regenerative
Bioengineering and Repair, Department of Surgery and Orthopaedic Surgery, UCLA
School of Medicine, Los Angeles, California. Tissue Engineering is the
application of the principles of life sciences and engineering to develop
biological substitutes for the restoration or replacement of tissue or organ
function.

Stem Cells are undifferentiated
cells in an embryo or adult which can undergo unlimited division and give rise
to one or several different cell types. In adults an undifferentiated cell from
which some renewable tissues (blood, skin, etc. ) are formed.

Human adipose tissue (fat)
obtained by suction-assisted lipectomy (i.e. liposuction) was processed to
obtain a fibroblast-like population of cells or a processed lipoaspirate (PLA).
These PLA cells can be maintained in vitro (outside the body) for extended
periods with stable population doubling and low levels of senescence.
Immunofluorescence and flow cytometry show that the majority of PLA cells are
mesodermal or mesenchymal origin with low levels of contaminating pericytes,
endothelial cells, and smooth muscle cells. Finally, PLA cells differentiate in
vitro into adipogenic (fat), chondrogenic (cartilage), myogenic (muscle), and
osteogenic (bone) cells in the presence of lineage-specific induction factors.
This pioneering study concludes that the data support the hypothesis that a
human lipoaspirate contains multipotent cells and may represent an alternative
stem cells source to bone marrow-derived MSCs (mesenchymal stem cells).

The discovery means that a
person's own fat might one day be used to provide the tissue needed to treat
disease or repair injured or worn-out parts. From cartilage implants in damaged
knees to brain implants for Parkinson's disease and strokes. Theoretically,
people might be able to get rid of their love handles while supplying the
material needed to fix a creaky knee or hip. Unlike a transplant, tissue created
by a person's owns stem cells would pose no risk of rejection or exposure to
viruses from a donor.

"Fat may be a practical source of
cells from which to make new tissues," said Dr. Marc H. Hedrick, the lead author
and an assistant professor of surgery and pediatrics at the university of
California at Los Angeles and the director of the study, in which researchers
from the University of Pittsburgh collaborated. "We don't yet know the limits
for stem cells found in fat," said Dr. Adam J. Katz of the University of
Pittsburgh, a co-author. " So far, we have seen promising results with all of
the tissue types we have examined." The Bush administration is contemplating to
ban the use of embryonic stem cells from aborted tissues, and hence this new
discovery offers an alternative source that could be much more abundant and much
less contentious. "This could take the air right out of the debate about
embryonic stem cells," said Dr. Hedrick. The newly identified cells have so many
different potential applications, he added, that "it makes it hard to argue that
we should use embryonic cells." "This changes the way we think about fat
tissue," Dr. Hedrick said. "It's not a static spare tire around our waist. It 's
really a dynamic tissue, and there are a lot of things in it that could help us
fix people with diseases." (NY Times April 10, 2001).

"This is extremely significant in
terms of its potential," said Dr. Michael T. Longaker of Stanford University.
"Unfortunately, fat is a substantial natural resource in the USA. This is a
great way to do something with it." (The Courier-Journal, Louisville, KY April
10, 2001)

During the 1990s, researchers
have found that adults also have stem cells in a variety of locations, ranging
from bone marrow, to the brain. Since they are present in small numbers and
recovering them could be difficult and painful. Small amounts of stem cells can
be extracted from bone marrow, but removing marrow from a patient can be
painful. For example to extract stem cells from the bone marrow requires
drilling a tiny hole directly in the bone, which remains painful for weeks after
the procedure. Furthermore the yield is small, usually about a few milliliters
(ml). Stem cells for research has been collected from bone marrow, brain or
fetal tissue. But the use of fetal tissue has provoked ethics disputes, and
performing brain surgery to harvest stem cells is not practical.

On the other hand Liposuction is
much easier to perform through an incision in the skin that about one inch long
and is relatively painless. And liters of fat is harvested and tossed
away-producing a thousand times as many stem cells as can be obtained from bone
marrow. In older adults, the percentage of stem cells is even higher in fat
cells than in bone marrow. Since each person serves as his or own fat donor,
there would be no problem with rejection of implanted cells. Researchers looked
for stem cells in fat because fat, marrow and bone in humans developed from the
same layer of embryonic tissue, the mesoderm, and tissues from the same origin
often had properties in common. So if bone marrow has stem cells, then it is
logical to think that fat should have them too. The researchers saved fat from
liposuction and processed it to isolate cells thought to include stem cells. To
get things revved up, the cells have to be fed with the right stuff.

To coax the cells to make bone,
for instance, the researchers used a medium containing calcium, phosphate and
vitamin C. They varied the conditions to grow cartilage, muscle or more fat
cells. Stem cells can be converted into specific tissues by exposing them to
complex mixture of growth hormones and other chemicals, which requires a
different formula for each desired tissue. The bottom line is finding what needs
to be included in each formulation.

The study was the first to find
stem cells in fat and use them to grow different tissues. Like any other study,
other researchers to find out whether the conclusions hold up must repeat it.
Another team at Duke University has produced similar results, turning stem cells
from fat into cartilage. "It's very important for different groups to reach the
same conclusion with a study with this much potential impact," said Dr. Farshid
Guilak, leader of the Duke study. Both the Stanford and Duke groups are
executing tissue examinations in animals, and both suggested that for the first
clinical trials to be conducted in humans, it may take up to five years.
Repairing of knees and other joints, as well as noses and ears by cartilage
implants will be the initial utilization of this discovery. Laboratory grown
Cartilage cells are being used in the reconstruction of damaged knees, but the
use of stem cells would astoundingly increase the supply of tissue available.
The organs and tissues that resist healing such as broken and impaired bones
could be repaired. This item is also high on the agenda. The stem cells might be
used for a much extensive diversity of applications, including brain implants
for Parkinson's disease and strokes (brain attacks), and in the repair of heart
tissues, are all possibilities in the future. Now, embryonic stem cells that
secrete vital hormones are used to treat victims of Parkinson's and Huntington's
diseases, for example.

In the adult human body most of
the cells are somatic cells. These somatic cells are called differentiated cells
and have adopted an indelible identity- skin, heart, muscle, whatever the case
and they cannot be changed. Skin cells, for example, cannot be converted into
bone, cartilage or brain tissue, or vice versa. But embryos have a large
percentage of genetically unprogrammed or undifferentiated cells that have the
potential to become any kind of cell in the body. All other cells stem from
these undifferentiated cells, hence the name stem cells them. The stem cells are
a premium for researchers and clinicians, but their use is highly disputed
because the only way to obtain them is through a miscarriage.

Even if they do, using fat to
provide tissue for patients is a long way off and a procedure for doing so is
not clear. Scientists must determine, for instance, whether stem cells can be
given to patients or whether the cells must be cultured in the laboratory to
turn them into the desired tissue, then implanted where needed. Actual tests
involving humans are likely five years away.

Eight years ago, President
Clinton reversed a ban on federal funding for research on embryonic stem cells,
but many observers believe that Bush administration officials will restore the
ban. Performing research on fetuses obtained from abortion or miscarriages has
become a political hotchpotch. Hence the scientific research community is taking
the wrath of the anti-abortion groups. In the eighties President Ronald Reagan
prohibited federal funding of research that utilized fetal tissue. They were
transplanting more matured cells to treat Parkinson's disease and in the
pancreas of diabetics. Our President Bush's father supported this ban when he
was President (1988-1992). When Bill Clinton became the President he reversed
the ban of his Republican predecessors. President Clinton's federally funded
fetal tissue research is continuing. As mentioned above, researchers have
already transplanted dopamine-producing cells from the fetal brain into patients
suffering from Parkinson's disease. What will happen to the destiny of stem cell
research using fetuses, under the present Bush administration is uncertain.